External electrical and pharmacological cardioversion for atrial fibrillation, atrial flutter or atrial tachycardias: a network meta-analysis.

BACKGROUND: Atrial fibrillation (AF) is the most frequent sustained arrhythmia. Cardioversion is a rhythm control strategy to restore normal/sinus rhythm, and can be achieved through drugs (pharmacological) or a synchronised electric shock (electrical cardioversion). OBJECTIVES: To assess the efficacy and safety of pharmacological and electrical cardioversion for atrial fibrillation (AF), atrial flutter and atrial tachycardias. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, Conference Proceedings Citation Index-Science (CPCI-S) and three trials registers (ClinicalTrials.gov, WHO ICTRP and ISRCTN) on 14 February 2023. SELECTION CRITERIA: We included randomised controlled trials (RCTs) at the individual patient level. Patient populations were aged ≥ 18 years with AF of any type and duration, atrial flutter or other sustained related atrial arrhythmias, not occurring as a result of reversible causes. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology to collect data and performed a network meta-analysis using the standard frequentist graph-theoretical approach using the netmeta package in R. We used GRADE to assess the quality of the evidence which we presented in our summary of findings with a judgement on certainty. We calculated differences using risk ratios (RR) and 95% confidence intervals (CI) as well as ranking treatments using a P value. We assessed clinical and statistical heterogeneity and split the networks for the primary outcome and acute procedural success, due to concerns about violating the transitivity assumption. MAIN RESULTS: We included 112 RCTs (139 records), from which we pooled data from 15,968 patients. The average age ranged from 47 to 72 years and the proportion of male patients ranged from 38% to 92%. Seventy-nine trials were considered to be at high risk of bias for at least one domain, 32 had no high risk of bias domains, but had at least one domain classified as uncertain risk, and one study was considered at low risk for all domains. For paroxysmal AF (35 trials), when compared to placebo, anteroapical (AA)/anteroposterior (AP) biphasic truncated exponential waveform (BTE) cardioversion (RR: 2.42; 95% CI 1.65 to 3.56), quinidine (RR: 2.23; 95% CI 1.49 to 3.34), ibutilide (RR: 2.00; 95% CI 1.28 to 3.12), propafenone (RR: 1.98; 95% CI 1.67 to 2.34), amiodarone (RR: 1.69; 95% CI 1.42 to 2.02), sotalol (RR: 1.58; 95% CI 1.08 to 2.31) and procainamide (RR: 1.49; 95% CI 1.13 to 1.97) likely result in a large increase in maintenance of sinus rhythm until hospital discharge or end of study follow-up (certainty of evidence: moderate). The effect size was larger for AA/AP incremental and was progressively smaller for the subsequent interventions. Despite low certainty of evidence, antazoline may result in a large increase (RR: 28.60; 95% CI 1.77 to 461.30) in this outcome. Similarly, low-certainty evidence suggests a large increase in this outcome for flecainide (RR: 2.17; 95% CI 1.68 to 2.79), vernakalant (RR: 2.13; 95% CI 1.52 to 2.99), and magnesium (RR: 1.73; 95% CI 0.79 to 3.79). For persistent AF (26 trials), one network was created for electrical cardioversion and showed that, when compared to AP BTE incremental energy with patches, AP BTE maximum energy with patches (RR 1.35, 95% CI 1.17 to 1.55) likely results in a large increase, and active compression AP BTE incremental energy with patches (RR: 1.14, 95% CI 1.00 to 1.131) likely results in an increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: high). Use of AP BTE incremental with paddles (RR: 1.03, 95% CI 0.98 to 1.09; certainty of evidence: low) may lead to a slight increase, and AP MDS Incremental paddles (RR: 0.95, 95% CI 0.86 to 1.05; certainty of evidence: low) may lead to a slight decrease in efficacy. On the other hand, AP MDS incremental energy using patches (RR: 0.78, 95% CI 0.70 to 0.87), AA RBW incremental energy with patches (RR: 0.76, 95% CI 0.66 to 0.88), AP RBW incremental energy with patches (RR: 0.76, 95% CI 0.68 to 0.86), AA MDS incremental energy with patches (RR: 0.76, 95% CI 0.67 to 0.86) and AA MDS incremental energy with paddles (RR: 0.68, 95% CI 0.53 to 0.83) probably result in a decrease in this outcome when compared to AP BTE incremental energy with patches (certainty of evidence: moderate). The network for pharmacological cardioversion showed that bepridil (RR: 2.29, 95% CI 1.26 to 4.17) and quindine (RR: 1.53, (95% CI 1.01 to 2.32) probably result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up when compared to amiodarone (certainty of evidence: moderate). Dofetilide (RR: 0.79, 95% CI 0.56 to 1.44), sotalol (RR: 0.89, 95% CI 0.67 to 1.18), propafenone (RR: 0.79, 95% CI 0.50 to 1.25) and pilsicainide (RR: 0.39, 95% CI 0.02 to 7.01) may result in a reduction in this outcome when compared to amiodarone, but the certainty of evidence is low. For atrial flutter (14 trials), a network could be created only for antiarrhythmic drugs. Using placebo as the common comparator, ibutilide (RR: 21.45, 95% CI 4.41 to 104.37), propafenone (RR: 7.15, 95% CI 1.27 to 40.10), dofetilide (RR: 6.43, 95% CI 1.38 to 29.91), and sotalol (RR: 6.39, 95% CI 1.03 to 39.78) probably result in a large increase in the maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: moderate), and procainamide (RR: 4.29, 95% CI 0.63 to 29.03), flecainide (RR 3.57, 95% CI 0.24 to 52.30) and vernakalant (RR: 1.18, 95% CI 0.05 to 27.37) may result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: low). All tested electrical cardioversion strategies for atrial flutter had very high efficacy (97.9% to 100%). The rate of mortality (14 deaths) and stroke or systemic embolism (3 events) at 30 days was extremely low. Data on quality of life were scarce and of uncertain clinical significance. No information was available regarding heart failure readmissions. Data on duration of hospitalisation was scarce, of low quality, and could not be pooled. AUTHORS' CONCLUSIONS: Despite the low quality of evidence, this systematic review provides important information on electrical and pharmacological strategies to help patients and physicians deal with AF and atrial flutter. In the assessment of the patient comorbidity profile, antiarrhythmic drug onset of action and side effect profile versus the need for a physician with experience in sedation, or anaesthetics support for electrical cardioversion are key aspects when choosing the cardioversion method.

Comparison between catheter ablation versus permanent pacemaker implantation as an initial treatment for tachycardia-bradycardia syndrome patients: a prospective, randomized trial.

BACKGROUND: Clinical outcomes after catheter ablation (CA) or pacemaker (PM) implantation for the tachycardia-bradycardia syndrome (TBS) has not been evaluated adequately. We tried to compare the efficacy and safety outcomes of CA and PM implantation as an initial treatment option for TBS in paroxysmal atrial fibrillation (AF) patients. METHODS: Sixty-eight patients with paroxysmal AF and TBS (mean 63.7 years, 63.2% male) were randomized, and received CA (n = 35) or PM (n = 33) as initial treatments. The primary outcomes were unexpected emergency room visits or hospitalizations attributed to cardiovascular causes. RESULTS: In the intention-to-treatment analysis, the rates of primary outcomes were not significantly different between the two groups at the 2-year follow-up (19.8% vs. 25.9%; hazard ratio (HR) 0.73, 95% confidence interval (CI) 0.25-2.20, P = 0.584), irrespective of whether the results were adjusted for age (HR 1.12, 95% CI 0.34-3.64, P = 0.852). The 2-year rate of recurrent AF was significantly lower in the CA group compared to the PM group (33.9% vs. 56.8%, P = 0.038). Four patients (11.4%) in the CA group finally received PMs after CA owing to recurrent syncope episodes. The rate of major or minor procedure related complications was not significantly different between the two groups. CONCLUSION: CA had a similar efficacy and safety profile with that of PM and a higher sinus rhythm maintenance rate. CA could be considered as a preferable initial treatment option over PM implantation in patients with paroxysmal AF and TBS. TRIAL REGISTRATION: KCT0000155.

Atrial fibrillation ablation compared to pacemaker therapy in patients with tachycardia-bradycardia syndrome: A systematic review and updated meta-analysis.

BACKGROUND: Tachycardia-bradycardia syndrome (TBS) is a subtype of sick sinus syndrome characterized by prolonged sinus pause (≥3 s) following termination of tachyarrhythmias, primarily atrial fibrillation (AF). There is controversy regarding whether the long-term prognosis of AF ablation is superior to pacemaker implantation. This study aimed to compare the effects of AF ablation and pacemaker therapy in patients with TBS. METHODS: We conducted a comprehensive search of electronic databases, including PubMed, Cochrane, EmBase, Web of Science, and Chinese BioMedical, up until December 1, 2023. We included studies that reported the effects of AF ablation vs pacemaker therapy in patients with TBS. From this search, we identified 5 studies comprising 843 participants with TBS who underwent catheter AF ablation or pacemaker therapy. RESULTS: Our meta-analysis revealed that AF ablation and pacemaker therapy had similar effects on cardiovascular death (odds ratio [OR] = 0.62 and 95% confidence interval [CI]: 0.14-2.65), procedural complications (OR = 1.53 and 95% CI: 0.67-3.48), and cardiovascular rehospitalization (OR = 0.57 and 95% CI: 0.26-1.22). However, AF ablation provided greater benefits than pacemaker therapy in terms of all-cause mortality (OR = 0.37 and 95% CI: 0.17-0.82), thromboembolism (OR = 0.25 and 95% CI: 0.12-0.49), stroke (OR = 0.28 and 95% CI: 0.13-0.57), heart failure (OR = 0.27 and 95% CI: 0.13-0.56), freedom from AF (OR = 23.32 and 95% CI: 7.46-72.92), and prevention of progression to persistent AF (OR = 0.12 and 95% CI: 0.06-0.24). Furthermore, AF ablation resulted in a reduced need for antiarrhythmic agents (OR = 0.21 and 95% CI: 0.08-0.59). CONCLUSION: AF ablation can effectively reduce the risk of all-cause mortality, thromboembolism, stroke, heart failure, and progression to persistent AF in patients with TBS. Additionally, it may eliminate the need for further pacemaker therapy in most cases after ablation. Therefore, AF ablation is considered superior to pacemaker therapy in the management of patients with TBS.

Adeno-associated virus-mediated gene therapy for cardiac tachyarrhythmia: A systematic review and meta-analysis.

Cardiac tachyarrhythmia presents a significant health care challenge, causing notable morbidity and mortality. Conventional treatments have limitations and potential risks, resulting in an elevated disease burden. Adeno-associated virus (AAV)-mediated gene therapy holds promise as a potential future treatment option. Therefore, we aimed to provide a measured overview of the latest developments in this rapidly growing field. PubMed and Embase databases were searched up to January 2024. Studies that employed AAV as a vector for delivery of therapeutic agents to treat cardiac tachyarrhythmia were included. Of the 26 studies included, 20 published in the last 5 years. There were 22 novel molecular targets identified. More than 80% of the included studies employed small-animal models or used AAV9. In atrial fibrillation preclinical studies, AAV-mediated gene therapy reduced atrial fibrillation inducibility by 81% (odds ratio, 0.19 [0.08-0.45]; P < .01). Similarly, for acquired and inherited ventricular arrhythmia, animal models receiving gene therapy had less inducible ventricular arrhythmia (odds ratio, 0.06 [0.03-0.11]; P < .01). This review highlights the rapid progress of AAV-mediated gene therapy for cardiac tachyarrhythmia. Although these investigations are currently in the early stages of clinical application, they present promising prospects for gene therapy. (PROSPERO registry: CRD42023479448).

Noninvasive Vagus Nerve Stimulation in Postural Tachycardia Syndrome: A Randomized Clinical Trial.

BACKGROUND: Low-level transcutaneous stimulation of the auricular branch of the vagus nerve at the tragus is antiarrhythmic and anti-inflammatory in animals and humans. Preliminary studies show that transcutaneous vagus nerve stimulation (tVNS) is beneficial in animal models of postural tachycardia syndrome (POTS). OBJECTIVES: In this study the authors conducted a sham-controlled, double-blind, randomized clinical trial to examine the effect of tVNS on POTS over a 2-month period relative to sham stimulation. METHODS: tVNS (20 Hz, 1 mA below discomfort threshold) was delivered using an ear clip attached to either the tragus (active; n = 12) or the ear lobe (sham; n = 14) for 1 hour daily over a 2-month period. Postural tachycardia was assessed during the baseline and 2-month visit. Heart rate variability based on 5-minute electrocardiogram, serum cytokines, and antiautonomic autoantibodies were measured at the respective time points. RESULTS: Mean age was 34 ± 11 years (100% female; 81% Caucasian). Adherence to daily stimulation was 83% in the active arm and 86% in the sham arm (P > 0.05). Postural tachycardia was significantly less in the active arm compared with the sham arm at 2 months (mean postural increase in heart rate 17.6 ± 9.9 beats/min vs 31.7 ± 14.4 beats/min; P = 0.01). Antiadrenergic autoantibodies and inflammatory cytokines were lower in the active arm compared with the sham arm at 2 months (P < 0.05). Heart rate variability was better in the active arm. No device-related side effects were observed. CONCLUSIONS: Our results support the emerging paradigm of noninvasive neuromodulation to treat POTS. Mechanistically, this effect appears to be related to reduction of antiautonomic autoantibodies and inflammatory cytokines, and improvement in autonomic tone. Further studies are warranted. (Autoimmune Basis for Postural Tachycardia Syndrome; NCT05043051).

Transition mechanisms from atrial flutter to atrial fibrillation during anti-tachycardia pacing therapy.

BACKGROUND: Atrial anti-tachycardia pacing (aATP) has been shown to be effective for the termination of atrial tachyarrhythmias, but its success rate is still not high enough. OBJECTIVE: The main objective of this study was to investigate the mechanisms of atrial flutter (AFL) termination by aATP and the transition from AFL to atrial fibrillation (AF) during aATP. METHODS: We developed a multi-scale model of the human atrium based on magnetic resonance images and examined the atrial electrophysiology of AFL during aATP with a ramp protocol. RESULTS: In successful cases of aATP, paced excitation entered the excitable gap and collided with the leading edge of the reentrant wave front. Furthermore, the excitation propagating in the opposite direction collided with the trailing edge of the reentrant wave to terminate AFL. The second collision was made possible by the distribution of the wave propagation velocity in the atria. The detailed analysis revealed that the slowing of propagation velocity occurred at the exit of the sub-Eustachian isthmus, probably due to source-sink mismatch. During the transition from AFL to AF, the excitation collided with the refractory zone of the preceding wave and broke into multiple wave fronts to induce AF. A similar observation was made for the transition from AF to sinus rhythm. In both cases, the complex anatomy of the atria played an essential role. CONCLUSION: The complex anatomy of atria plays an essential role in the maintenance of stable AFL and its termination by aATP, which were revealed by the realistic three-dimensional simulation model.

[Radiofrequency transcatheter ablation of the left lateral Kent bundle in a premature newborn after 28 weeks of pregnancy with prenatal diagnosis of incessant tachycardia: 28-year follow-up]. / Ablazione transcatetere di fascio accessorio tipo Kent sinistro laterale in nato prematuro a 7 mesi di gestazione con diagnosi prenatale di tachicardia incessante: follow-up a distanza di 28 anni.

A case of incessant tachycardia diagnosed at the seventh month of pregnancy conditioning hydrops fetalis is described. Delivery was induced by caesarean section. Atrioventricular reciprocating tachycardia was due to the involvement of a left lateral accessory pathway refractory to multiple antiarrhythmic drugs and was often associated with ipsilateral left bundle branch block at a slower rate. To the best of our knowledge, this is the smallest premature infant in whom radiofrequency catheter ablation was necessary. There were no complaints of complications with recognizable clinical involvement but only a pericardial effusion diagnosed by echocardiography that reabsorbed within a few days. At 28 years old, the psycho-somatic development of this young man is optimal, with normal findings at cardiac imaging. This treatment modality has proven feasible but remains a procedure to be performed only in exceptional cases by very experienced operators.

[Tachyarrhythmias in congenital heart disease patients: diagnosis, clinical presentation and treatment]. / Tachiaritmie nel paziente con cardiopatia congenita: diagnosi, presentazione clinica e trattamento.

Tachyarrhythmias are a major cause of morbidity and mortality in adult congenital heart disease patients. There is a strong association between tachyarrhythmias and the specific congenital heart disease and the patient's surgical history. Health care for adults with congenital heart disease and arrhythmias should be coordinated by adult congenital heart disease centers of excellence that serve as a resource for consultation and referral. A complete and multidisciplinary evaluation of patients with tachyarrhythmias, including a detailed hemodynamic and electrophysiological evaluation, is mandatory to define the best treatment strategy.

Progression from paroxysmal to persistent atrial fibrillation in pacemaker patients with tachycardia-bradycardia syndrome: a multicenter study.

Progression from paroxysmal to persistent atrial fibrillation (AF) is occasionally encountered in patients with previous pacemaker implantation (PMI) for the treatment of tachycardia-bradycardia syndrome (TBS). We aimed to determine the rate of its incidence occurring within the early years after PMI and the predictors. We studied TBS patients who received PMI at 5 core cardiovascular centers. The end point was a conversion from paroxysmal to persistent AF. We extracted 342 TBS patients out of 2579 undergoing PMI. During 5 ± 3.1 years of follow-up, 114 (33.3%) reached the end point. The time to the end point was 2.9 ± 2.7 years. The event rates within a year and 3 years after the PMI were 8.8% and 19.6%, respectively. In the multivariate hazard analyses, hypertension (hazard ratio [HR] 3.2, P = 0.03) and congestive heart failure (HR 2.1, P = 0.04) were found to be independent predictors of the end point occurring within a year after the PMI. Congestive heart failure (HR 1.82, P = 0.04), left atrial diameter of ≥ 40 mm (HR 4.55, P < 0.001), and the use of antiarrhythmic agents (HR 0.58, P = 0.04) were independently associated with the 3-year end point. Prediction models including combinations of those 4 parameters for the 1- and 3-year incidence both exhibited a modest risk discrimination (both c-statistics 0.71). In conclusion, early progression from paroxysmal to persistent AF was less frequent than expected in the TBS patients with PMI. Factors related to atrial remodeling and no use of antiarrhythmic drugs may facilitate the progression.

Diagnosis and management of patients who present with narrow complex tachycardia in the emergency department.

INTRODUCTION: While narrow complex tachycardia (NCT) is a common presentation to the emergency department (ED), little is known about its incidence in the ED or about emergency physician expertise in its diagnosis and management. We sought to compare cases of NCT due to primary arrhythmias to those with a rapid heart rate secondary to a medical issue, as well as to determine the accuracy of ED physician diagnosis and appropriateness of treatment. METHODS: We conducted a health records review at a large academic hospital ED staffed by 95 physicians and included consecutive adult patients over 7 months (2020-2021) with NCT (heart rate ≥ 130 bpm and QRS < 120 ms). Cases were reviewed for accuracy of ECG diagnosis and for correctness of treatment as per guidelines by an adjudication committee. RESULTS: We identified 310 ED visits (0.8% of all ED visits), mean age 65.1 years, 52.6% female. Primary arrhythmias accounted for 54.8%. ED physicians correctly interpreted 86.6% of ECGs. The most common arrhythmias and accuracy of ED physician ECG interpretation were atrial fibrillation 44.5% (95.1%), sinus tachycardia 24.2% (90.5%), atrial flutter 15.8% (61.5%), and supraventricular tachycardia (SVT) 12.9% (81.6%). Treatments were judged optimal in 96.5% of primary NCT and 99.3% in secondary NCT. Treatments were suboptimal for failure to reduce heart rate < 100 bpm prior to discharge in 2.1% of primary cases and failure to treat underlying cause in 0.7% of secondary cases. CONCLUSION: NCT was found in 0.8% of all ED visits, with more being primary NCT. ED physicians correctly interpreted 86.6% of ECGs but had difficulty differentiating atrial flutter and SVT. They implemented appropriate care in most cases but sometimes failed to adequately control heart rate or to treat the underlying condition, suggesting opportunities to improve care of NCT in the ED.

RéSUMé: INTRODUCTION: Bien que la tachycardie à complexe QRS étroite (narrow complex tachycardia [NCT]) soit une présentation courante au service des urgences (SU), on sait peu de choses sur son incidence dans le SU ou sur l'expertise des médecins urgentistes dans son diagnostic et sa prise en charge. Nous avons cherché à comparer les cas de NCT dus à des arythmies primaires à ceux avec une fréquence cardiaque rapide secondaire à un problème médical, ainsi que pour déterminer l'exactitude du diagnostic de médecin ED et la pertinence du traitement. MéTHODES: Nous avons effectué un examen des dossiers médicaux dans les urgences d'un grand hôpital universitaire où travaillent 95 médecins et avons inclus des patients adultes consécutifs sur 7 mois (2020-2021) présentant une NCT (fréquence cardiaque ≥ 130 bpm et QRS < 120 ms). Les cas ont été examinés par un comité d'adjudication pour vérifier l'exactitude du diagnostic ECG et la justesse du traitement conformément aux directives. RéSULTATS: Nous avons recensé 310 visites aux urgences (0,8 % de toutes les visites aux urgences), l'âge moyen étant de 65,1 ans, 52,6 % de femmes. Les arythmies primaires représentaient 54,8 %. Les médecins urgentistes ont correctement interprété 86,6 % des ECG. Les arythmies les plus fréquentes et la précision de l'interprétation de l'ECG par le médecin de l'urgence étaient la fibrillation auriculaire 44,5 % (95,1 %), la tachycardie sinusale 24,2 % (90,5 %), le flutter auriculaire 15,8 % (61,5 %) et la tachycardie supraventriculaire (TSV) 12,9 % (81,6 %). Les traitements ont été jugés optimaux dans 96,5 % des NCT primaires et 99,3 % des NCT secondaires. Les traitements étaient sous-optimaux en raison de l'incapacité à réduire la fréquence cardiaque < 100 bpm avant la sortie de l'hôpital dans 2,1 % des cas primaires et de l'incapacité à traiter la cause sous-jacente dans 0,7 % des cas secondaires. CONCLUSION: Une NCT a été constatée dans 0,8 % de toutes les visites aux urgences, la plupart étant des NCT primaires. Les médecins des services d'urgence ont interprété correctement 86,6 % des ECG mais ont eu des difficultés à différencier le flutter auriculaire et la TSV. Ils ont mis en œuvre des soins appropriés dans la plupart des cas, mais n'ont parfois pas réussi à contrôler adéquatement la fréquence cardiaque ou à traiter l'affection sous-jacente, ce qui laisse entrevoir des possibilités d'améliorer la prise en charge des NCT aux urgences.

Atrial tachyarrhythmias after lung transplantation in children: A common occurrence.

BACKGROUND: Atrial arrhythmia's (AA) following lung transplant in adults are a well-described clinical finding. In pediatrics, however, there are limited data with some reports suggesting that arrhythmias are rare. METHODS: We performed a single-center retrospective review of lung transplant recipients from January 2013 to June 2020. A detailed evaluation of clinical characteristics, presence of arrhythmias, and outcomes was completed. Arrhythmias were documented based on inpatient telemetry or remote Holter monitoring. Analyses assessing risk factors for arrhythmias and associations with clinical outcomes were performed. RESULTS: Ninety-one lung transplants were performed in 90 patients. Post-operative AA occurred following 19% transplants. Ectopic atrial tachycardia was seen in 14%, atrial flutter in 2%, and a combination in 2%. The majority of these arrhythmias occurred within the first 45 days post-operatively. Antiarrhythmic treatment was required in 59%, but none required ablation or electrical cardioversion. In patients followed for a year or more, 88% had resolution of their arrhythmia. Arrhythmias were not associated with mortality. In further analysis, however, the presence of arrhythmia was associated with an increased length of ICU stay (median of 12 days (IQR 6, 23) versus 5 days (IQR 4, 9); p = .019) and overall length of hospital stay (median of 26 days (IQR 19, 36) versus 17 days (IQR 19, 36); p = .043). CONCLUSIONS: Atrial tachyarrhythmias after lung transplantation are common in the pediatric population and usually occur early. Although they frequently require medical therapy and are associated with longer stays, there is no associated increased mortality. In addition, the arrhythmias typically self-resolve.

Narrow Complex Tachycardias.

Narrow-complex tachycardias are commonly seen on shift in the emergency department. Although a portion of patients present with hemodynamic instability because of arrhythmia, it is important to know that the tachycardia can be a result of an underlying condition. Rapid identification of the type and etiology of the arrhythmia is vital to directing appropriate management strategies and disposition decisions.

Patient-activated anti-tachycardia pacing in adult congenital heart disease.

INTRODUCTION: In adults with congenital heart disease, intra-atrial reentrant tachycardia (IART) is a common arrhythmia that causes significant morbidity and mortality. One treatment option for IART is antitachycardia pacing. Atrial antitachycardia pacing algorithms deliver therapy for IART with ≥2:1 conduction, but most algorithms will not recognize IART with 1:1 conduction. Temporary Patient Activated Rx (TPARx) is Medtronic software that can be installed in antitachycardia pacemakers allowing patients to deliver therapies on demand for IART with 1:1 conduction. METHODS: Retrospective chart review at a single institution of all patients who had TPARx installed into their pacemaker. RESULTS: Four adults with single ventricle congenital heart disease and IART underwent Fontan conversion, arrhythmia surgery, and placement of an epicardial dual-chamber antitachycardia pacemaker. They had recurrent IART with a long cycle length and 1:1 conduction that failed to trigger antitachycardia pacing therapies. TPARx software was programmed into their pacemakers to allow recognition and treatment of IART with 1:1 conduction. Mean follow-up duration after TPARx programming was 4.9 years. Each patient received at least one successful antitachycardia pacing therapy via TPARx - range 0.4-26 treated IART episodes per year. There were no atrial or ventricular arrhythmias induced with antitachycardia pacing. Two patients were able to discontinue anticoagulation after TPARx installation. CONCLUSION: This series demonstrates the use of TPARx software as part of a long-term IART management strategy in select patients with IART who have failed more conventional therapies.

Resultados de la ablación con catéter con mínimo o nulo empleo de fluoroscopia en pacientes pediátricos con taquiarritmias supraventriculares / Results of catheter ablation with zero or near zero fluoroscopy in pediatric patients with supraventricular tachyarrhythmias

Introducción y objetivos: La exposición a radiación ionizante en los procedimientos de ablación conlleva riesgos para la salud, sobre todo en pacientes pediátricos. Nuestro objetivo es comparar la seguridad y la eficacia de la ablación guiada por un sistema de navegación intracardiaca no fluoroscópica (SNINF) con las de la ablación guiada exclusivamente por fluoroscopia en pacientes pediátricos. Métodos: Se analizaron los resultados de la ablación con catéter en pacientes pediátricos con vías accesorias de riesgo o taquicardias supraventriculares remitidos a nuestro centro en un periodo de 6 años. Se compararon los procedimientos guiados solo por fluoroscopia (grupo A) y los guiados por SNINF (grupo B). Resultados: Se analizaron 120 procedimientos de ablación en 110 pacientes (edad, 11±3,2 años; el 70% varones), 62 procedimientos en el grupo A y 58 en el grupo B. No se encontraron diferencias significativas entre ambos grupos en éxito del procedimiento (el 95% del grupo A y el 93,5% del grupo B; p=0,53), complicaciones (el 1,7 frente al 1,6%; p=0,23) y recurrencia (el 7,3 frente al 6,9%; p=0,61). Sin embargo, el tiempo de fluoroscopia (mediana, 1,1 frente a 12 min; p<0,0005) y el tiempo de ablación (mediana, 96,5 frente a 133,5 s; p=0,03) fueron menores en el grupo B. La presencia de cardiopatía se comportó como un predictor independiente de recurrencia (p=0,03). Conclusiones: El SNINF para guiar los procedimientos de ablación en pacientes pediátricos reduce el tiempo de exposición a la radiación ionizante. Su empleo generalizado en las ablaciones pediátricas podría reducir el riesgo atribuido a la radiación (AU)

Introduction and objectives: Ionizing radiation exposure in catheter ablation procedures carries health risks, especially in pediatric patients. Our aim was to compare the safety and efficacy of catheter ablation guided by a nonfluoroscopic intracardiac navigation system (NFINS) with those of an exclusively fluoroscopy-guided approach in pediatric patients. Methods: We analyzed catheter ablation results in pediatric patients with high-risk accessory pathways or supraventricular tachycardia referred to our center during a 6-year period. We compared fluoroscopy-guided procedures (group A) with NFINS guided procedures (group B). Results: We analyzed 120 catheter ablation procedures in 110 pediatric patients (11±3.2 years, 70% male); there were 62 procedures in group A and 58 in group B. We found no significant differences between the 2 groups in procedure success (95% group A vs 93.5% group B; P=.53), complications (1.7% vs 1.6%; P=.23), or recurrences (7.3% vs 6.9%; P = .61). However, fluoroscopy time (median 1.1minutes vs 12minutes; P <.0005) and ablation time (median 96.5seconds vs 133.5seconds; P=.03) were lower in group B. The presence of structural heart disease was independently associated with recurrence (P=.03). Conclusions: The use of NFINS to guide catheter ablation procedures in pediatric patients reduces radiation exposure time. Its widespread use in pediatric ablations could decrease the risk of ionizing radiation (AU)

Post COVID-19 Syndrome ("Long COVID") and Diabetes: Challenges in Diagnosis and Management.

BACKGROUND AND AIMS: Post Covid-19 syndrome (PCS) is a major cause of morbidity. In this article we intend to review the association and consequences of PCS and diabetes. METHODS: We reviewed all studies on "Long Covid", "Post COVID-19 Syndrome" and diabetes in PubMed and Google Scholar. RESULTS: The symptoms of PCS can be due to organ dysfunction, effects of hospitalisation and drugs, or unrelated to these. Type 2 diabetes mellitus has a bidirectional relationship with COVID-19. Presence of diabetes also influences PCS via various pathophysiological mechanisms. COVID-19 can add to or exacerbate tachycardia, sarcopenia (and muscle fatigue), and microvascular dysfunction (and organ damage) in patients with diabetes. CONCLUSION: PCS in patients with diabetes could be detrimental in multiple ways. Strict control of diabetes and other comorbidities, supervised rehabilitation and physical exercise, and optimal nutrition could help in reducing and managing PCS.

Bidirectional ventricular tachycardia induced by respiratory alkalosis mediated hypokalemia in a patient with acute ischemic heart failure.

Bidirectional ventricular tachycardia (BVT) is a rare arrhythmia that is generally observed in patients with catecholaminergic ventricular tachycardia or digoxin overdose. Herein, we present a case of BVT and electrical storm (ES) in an acute ischemic heart failure patient that is typically induced by hypokalemia. The patient was in invasive mechanical ventilator (MV) support and hypokalemia was related to acute respiratory alkalosis and that caused refractory hypokalemia despite intravenous (IV) potassium replacement. We also discuss our approach to solve refractory hypokalemia caused by respiratory alkalosis.

[Life-threatening cardiac arrhythmias]. / Akut lebensbedrohliche Herzrhythmusstörungen.

Cardiac arrhythmias are a common phenomenon and can be a challenge for the treating physicians in the acute situation. The article presents the different bradycardic and tachycardic cardiac arrhythmias and their treatment with practical advices for diagnosis.